Question

Draw the kinetic and thermodynamic enolates formed when 3-methylbutan-2-one (methyl isopropyl ketone) is treated with base. Include charges. Draw the oxyanion species;do not draw carbanion resonance forms.

Answer 1

===Concepts and reason===

Kinetic Enolates

The base deprotonates the less hindered alpha hydrogen at low temperature, giving the kinetic enolate anion with less substituted C=C double bond as the major product. This enolate is less stable but it is formed very fast.

Thermodynamic Enolates

The base deprotonates the highly hindered alpha hydrogen, giving the thermodynamic enolate anion with a more substituted C=C double bond as the major product. This enolate is more thermodynamically stable.

===Fundamentals===

Formation of the Kinetic Enolates (Oxyanion)

Consider an unsymmetrical ketone containing two different alpha hydrogen atoms (chemically nonequivalent hydrogen atoms):

Formation of Thermodynamic Enolates (Oxyanion)

Consider an unsymmetrical ketone containing two different alpha hydrogen atoms:

===ANSWER===

Answer 2